1. Field of the Invention
The present invention relates to a robot system equipped with a camera capturing an image of a target mark.
2. Description of the Related Art
A robot is sometimes used together with a machine tool for handling a workpiece. To facilitate the manual operation of the robot or to remotely control the robot using a controller of the machine tool, further, it is important to determine the positional relationship between the coordinate system of the machine tool and the coordinate system of the robot.
To determine the positional relationship between the coordinate system of a machine tool and a robot coordinate system, at least three points where the position of the machine tool and the position at the robot coordinate system are known are required. A touchup process bringing the tool center point (TCP) of the robot into physical contact with a predetermined point and measuring the 3D position of that point is known. Further, a method of using a 3D sensor attached to a hand of a robot to measure the 3D position of a predetermined point by a noncontact means is known.
Japanese Patent Publication No. 2011-048467A discloses to utilize a known positional relationship between a robot control point and a set point to find the positional relationship between a robot coordinate system and a coordinate system of a machine tool. Japanese Patent Publication No. 2005-201824A and Japanese Patent Publication No. 2010-117223A disclose using a camera to capture images of a plurality of positions to measure the 3D position of an object.